关键词: SnO₂纳米晶, 水热合成, 焙烧

Abstract: In this paper, we report our research on morphologically selective synthesis of nanocrystalline SnO₂ by the combination of hydrothermal preparation and calcinated process. We firstly prepared SnO₂ nanocrystals by the hydrothermal method at 140 ℃ for 3 h, using SnCl 4 as the reactant. With the initial pHof 1.8 or 1.34, we prepared uniform and well dispersed SnO₂(tetragonal) nanocrystals, with similar size of about 3 nm, as determined by TEM. However, after being calcinated at 500 ℃ for 2 h, specimen₁ prepared at pH=1.8 showed the rod like shape with an average size of 5 nm×20 nm, while the other one(specimen 2) prepaed at pH=1.34 showed a granular shape with an average size of 10 nm. XRDexperiments showed that specimen₁ had a new diffraction peak after calcination, which was contributed by the (023) face of orthorhombic SnO₂. The experiment results indicated that the morpholgy of SnO₂ nanocrystals after calcination was closely related to the initial acidity of the reaction solution, possibly due to the difference in surface properties, e.g. the difference in crystalline faces exposed to the surface of particals, under different hydrothermal conditions.

Key words: SnO₂ Nanocrystals, Hydrothermal synthesis, Calcination